Rotary screen repeat size in pixels: 640, 820, 914, 1018 mm

On a rotary screen machine, the screen is a nickel cylinder. Every turn of the cylinder prints one fixed length of cloth, and that length is the screen's repeat size.

This page gives you the pixel sizes for the four common screens at 150, 200 and 300 DPI, shows how the numbers were rounded, and explains how to fit a design so the mill does not send it back.

What the repeat size means

Screen makers list rotary screens by "repeat (circumference)": 530, 640, 688, 725, 819, 914 and 1018 mm are standard sizes. SPGPrints builds its RD8 machine with repeats from 640 to 1018 mm, and Indian machine listings from Surat show the same 640 to 1018 mm range.

The number is the distance around the cylinder. A 640 mm screen prints exactly 640 mm of fabric per turn, then starts again at the same point.

Repeat (circumference)	Diameter (circumference ÷ 3.1416)
640 mm	about 204 mm
819 mm	about 261 mm
914 mm	about 291 mm
1018 mm	about 324 mm

Note: Some online listings call 640 mm the "diameter". It is the circumference. If you measure across the end of a 640 mm screen you get about 20 cm.

The screen's length is a separate number. It runs across the fabric, from about 1,280 mm to 3,500 mm, and sets the widest cloth the machine can print.

Why the repeat must divide exactly

Your design's vertical repeat has to equal the circumference, or fit into it a whole number of times. If it does not, the pattern breaks once per turn and you see a joint line across the fabric every 640 mm.

For a 640 mm screen, these vertical repeats work:

• 640 mm (one per turn)
• 320 mm (two per turn)
• 213.33 mm (three per turn)
• 160 mm (four per turn)

Anything else, such as 300 mm, leaves a gap or an overlap. Across the width there is no such rule, because the tile just repeats along the length of the screen.

Pixel sizes for each screen

The conversion is simple: millimetres ÷ 25.4 gives inches, and inches × DPI gives pixels. Each value below is rounded to the nearest whole pixel; the exact figure is in brackets where rounding changes it.

640 mm screen (25.20 in)

Repeats per turn	Repeat height	150 DPI	200 DPI	300 DPI
1	640 mm	3,780 px (3,779.53)	5,039 px (5,039.37)	7,559 px (7,559.06)
2	320 mm	1,890 px (1,889.76)	2,520 px (2,519.69)	3,780 px (3,779.53)
3	213.33 mm	1,260 px (1,259.84)	1,680 px (1,679.79)	2,520 px (2,519.69)
4	160 mm	945 px (944.88)	1,260 px (1,259.84)	1,890 px (1,889.76)

819 or 820 mm screen (32.24 in)

Screen makers list this size as 819 mm. Many Indian sellers write 820 mm. At 300 DPI the two differ by 12 px (9,673 vs 9,685), so ask which figure your engraver uses.

Repeats per turn	Repeat height	150 DPI	200 DPI	300 DPI
1	819 mm	4,837 px (4,836.61)	6,449 px (6,448.82)	9,673 px (9,673.23)
2	409.5 mm	2,418 px (2,418.31)	3,224 px (3,224.41)	4,837 px (4,836.61)
3	273 mm	1,612 px (1,612.20)	2,150 px (2,149.61)	3,224 px (3,224.41)

914 mm screen (35.98 in)

Repeats per turn	Repeat height	150 DPI	200 DPI	300 DPI
1	914 mm	5,398 px (5,397.64)	7,197 px (7,196.85)	10,795 px (10,795.28)
2	457 mm	2,699 px (2,698.82)	3,598 px (3,598.43)	5,398 px (5,397.64)
3	304.67 mm	1,799 px (1,799.21)	2,399 px (2,398.95)	3,598 px (3,598.43)

1018 mm screen (40.08 in)

Repeats per turn	Repeat height	150 DPI	200 DPI	300 DPI
1	1018 mm	6,012 px (6,011.81)	8,016 px (8,015.75)	12,024 px (12,023.62)
2	509 mm	3,006 px (3,005.91)	4,008 px (4,007.87)	6,012 px (6,011.81)
3	339.33 mm	2,004 px (2,003.94)	2,672 px (2,671.92)	4,008 px (4,007.87)

For any other length, our fabric DPI calculator does the same sum.

Does rounding matter

One pixel at 300 DPI is 0.085 mm (25.4 ÷ 300), and at 150 DPI it is 0.17 mm. Rounding moves the repeat by less than that, which is far below what cloth stretches on the machine.

Write the repeat in millimetres in the file name as well, for example "rose_640mm_2rpt_8col.tif". Then the engraver works from the true size.

Tip: At 254 DPI one millimetre is exactly 10 pixels, so a 640 mm repeat is 6,400 px and 819 mm is 8,190 px with no rounding at all. Ask your engraver before you use it, since many mills expect 300 DPI.

Width and the horizontal repeat

The width of the design runs along the screen's length. Common Indian fabric widths at 300 DPI are 44 in × 300 = 13,200 px and 58 in × 300 = 17,400 px.

You do not need to make one giant file of the whole width. Send one seamless tile, and the engraver steps it across the screen.

A half-drop works too. Each tile drops by half its height as it steps across, and the full vertical repeat still divides the circumference.

Fitting a design to a screen

Most designs arrive at a repeat that matches no screen. Do the maths before you resize, and choose the screen that needs the smallest change.

Example: A digital design has a 300 mm repeat. On a 640 mm screen you must stretch it to 320 mm (+6.7%) or shrink it to 213.33 mm (-28.9%). On a 914 mm screen, three repeats of 304.67 mm fit with only +1.6%.

The Textile School calculator notes that a change above about 3% becomes visible on geometric designs, while florals hide more. So the 914 mm screen is the better choice here, if your printer has one.

Steps in Photoshop:

1. Work out the target repeat in pixels from the tables above.
2. Go to Image > Image Size, keep the width and height linked, and set the height to the target. Resample with Bicubic.
3. Crop or extend the width only if the motifs need it. Stretching just the height distorts round shapes.
4. Check the joins with Filter > Other > Offset: shift by half the width and half the height with "Wrap Around" on. Any seam now runs through the middle where you can see it.
5. Fix the seam, run Offset back, and save the tile at the final size.

Warning: Resize before you separate. If you stretch a file that already has trapping and spot channels, the overlaps stretch too and the screens may not register.

Common mistakes

• Treating 640 mm as the diameter and sending a 204 mm repeat.
• Using a repeat like 300 or 330 mm that does not divide any screen.
• Assuming 819 and 820 mm are the same file at 300 DPI.
• Stretching only the height to hit a repeat, so circles become ovals.
• Checking the seam only at 100% on the flat file. Run Offset, then look at a printed strike-off.
• Sizing for a screen the mill does not have. Ask first which repeat heads are on the machine.

What to send the mill

Send one tile at final size, with the repeat in mm, the screen size, the DPI and the colour count written in the file name or a note. Most mills want one spot channel per screen; read our textile colour separation guide for that step.

If your design is too small for the repeat at 300 DPI, enlarge it with the AI image upscaler before you fit it to the screen.

When it is sized and seamless, the next job is splitting it into screens. Our Channel Separation tool for that is coming soon, so join the waitlist to hear when it opens.